Abstract: This is an article in the field of ceramics and composites. In order to improve the performance of fly ash-based porous ceramic materials, the samples were surface-treated using Al₂O₃ modifying liquid, and physical and mechanical properties, adsorption effects and microscopic experiments were carried out on them. The results showed that the higher the sintering temperature, the smaller the porosity and water absorption of the porous ceramics, and the greater the strength and apparent density. Optimal sintering and molding of porous structures at a temperature of 1100 °C. When the concentration of Al₂O₃ modifying liquid was increased from 0 to 50 mol/L, the saturated adsorption rate of the porous ceramics increased about 6 times, and at the same time, the densities and strengths were also significantly increased. The surface modification effect of the Al₂O₃ modifying liquid promotes the formation of the caliche feldspar crystals, which results in a significant increase in the strength and adsorption properties of the porous ceramics. strength and adsorption performance were significantly improved.